From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CA330CCFA04 for ; Tue, 4 Nov 2025 11:33:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F2E9D8E0132; Tue, 4 Nov 2025 06:33:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EDFCF8E0124; Tue, 4 Nov 2025 06:33:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E1D408E0132; Tue, 4 Nov 2025 06:33:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id CD8858E0124 for ; Tue, 4 Nov 2025 06:33:16 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 8006D1A04AA for ; Tue, 4 Nov 2025 11:33:16 +0000 (UTC) X-FDA: 84072713592.15.0A3F331 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf08.hostedemail.com (Postfix) with ESMTP id D214C16000B for ; Tue, 4 Nov 2025 11:33:14 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762255994; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6WOQeTavzPrauVi8MwJO524evgvZo3Tkv1ShmH0pjuo=; b=2CD3qSpGokA9d5SgJKFHRKLlsB3oR1B9UsgcrdYdGsWdLCHkSdFeUmROC+pTNIgEcyjcT5 85swIx8EHA7xiV7Slzm/beN81tleFaV7ekNTciudCeALnhABZ2mLQsCkbNDGTgpR5F8Vbn e9JgvKNKFEM13C39HSto+cvBI8VwCrA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762255995; a=rsa-sha256; cv=none; b=3VEEt9wHm2fYjNYkTXkC7E+w9OpOOcMr04ISZjagz8Me7qw2bC3/rHww3YnW3a4oEYgo+s RfgQp70xS8VQ8TAbMyWXw8/L20HHHjGsjMAB4QVZLZhdwQRUUaxdoLEng1mzo4rlaGc00X gtGnQBnUdq8ikqmUKJlFI5/W8PIbb+8= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com; dmarc=pass (policy=none) header.from=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D06201C2B; Tue, 4 Nov 2025 03:33:05 -0800 (PST) Received: from [10.1.38.100] (e126510-lin.cambridge.arm.com [10.1.38.100]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C979F3F63F; Tue, 4 Nov 2025 03:33:06 -0800 (PST) Message-ID: Date: Tue, 4 Nov 2025 11:33:03 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 09/12] powerpc/mm: replace batch->active with in_lazy_mmu_mode() To: David Hildenbrand , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-10-kevin.brodsky@arm.com> <05e2062c-1689-44e7-9cc6-697646ca075d@redhat.com> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <05e2062c-1689-44e7-9cc6-697646ca075d@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: D214C16000B X-Stat-Signature: maixninq3mhjykout69hu5mderodzytx X-Rspam-User: X-HE-Tag: 1762255994-364415 X-HE-Meta: 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 lAxnxe8o j1uf+0RxqKV4Rdiq/mP61SpQz6BUvGlM4s1IucU42gZqA6bdSlQJUawZtf653hMW+Gw6u5AE+RJTzZlw6Cz7PTTHxGe3g6gnFhivctHWbmZ2dzyQNnHEt66dS6N1cumNeEFyEqfkMCFVAnyMFfINlMfgx7dvnU3bTuF1sMm/a6MV5pndboZfQa9WXty9XPXO/EOrN5LZYXAJzWPc3dm9E2WdT3154H+2WKajsDzGWI/oS551Mhp/JmFDn8rMbAyIpOzK2e1pO2cxCNZ6I3X6WGhSuMQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 03/11/2025 16:05, David Hildenbrand wrote: > On 29.10.25 11:09, Kevin Brodsky wrote: >> A per-CPU batch struct is activated when entering lazy MMU mode; its >> lifetime is the same as the lazy MMU section (it is deactivated when >> leaving the mode). Preemption is disabled in that interval to ensure >> that the per-CPU reference remains valid. >> >> The generic lazy_mmu layer now tracks whether a task is in lazy MMU >> mode. We can therefore use the generic helper in_lazy_mmu_mode() >> to tell whether a batch struct is active instead of tracking it >> explicitly. >> >> Signed-off-by: Kevin Brodsky >> --- > > I suspect you were not able to test this on real HW. Some help from > the ppc folks would be appreciated. Indeed, it would be nice to get some testing on ppc HW that actually uses lazy MMU (!radix_enabled()). > > LGTM, but the interaction with pause/resume adds a bit of complication > on top. Does it? This series doesn't change when arch_enter() and arch_leave() are called, batch->active and in_lazy_mmu_mode() should coincide.  - Kevin